Back from seein Harry Potter. Don't want to spoil the movie for anyone, so my opinions are behind the cut.
I'll try and go as chronologically as I can, but I'm sure there'll be a few times where I don't, so you'll have to forgive me.
First off, WTF is with the opening scene? o_O Know the bit where Voldemort is in the room with Wormtail in his father's old house? Well, yeah, who else was there? NO ONE! Just the two of them and Nagini. Well not in the movie. They decided "Hey! Let's put Barty Crouch Jr. in there too!" which makes NO sense at all. :-s He'd been sent to Hogwarts by then, Voldemort even says so in the book. AND Barty calls him Voldemort, not the Dark Lord, when everyone knows Death Eaters NEVER say his name. And he says it more than once too.
Quidditch World Cup was totally butchered. I can understand them not showing every single little thing, but it's like one minute they're there and then they're back in the tent. Actually, that's just how it is. :-s And then the Death Eater bit was sooo wrong. Harry did not get split up from Hermione and the others, and he definitely didn't get knocked out. AND he NEVER saw Barty. That was SOOO wrong. It wasn't even in the woods, it was in the actual campsite. :-s How hard is it to do it in the woods? Or to have Barty invisible? Come on! JK had these things for a reason!
The Dark Mark wasn't as intimidating/scary as I expected, but that's forgiveable. :-p
Beauxbatons and Durmstrang arrived almost instantly, it was like they arrived in September rather than at Halloween. Anyone know the deal with Beauxbatons being all girls, even though JK actually mentions there being guys there too? :-s And Dumbledore pronounced it so un-French like, like batons rather than "batons" meaning wands in French. But meh, that's minor. Though it was weird how AFTER they arrived at the castle he announced to the students that they'd be coming. Kinda like "well duh! They're already here, we SAW them arrive."
Very little Sirius in the movie which was kinda sad cos he rawks! And he's dying in the next one, he's gonna end up with a total of 30 minutes screen time between the 3 movies he's been in.
Dumbledore was quite rough, which is totally out of character. The way he grabs Harry and sorta demands the answers from him after his name comes out of the Goblet of Fire is so wrong. :\ Dumbledore's a gentle kind person, he wouldn't grab a student and kinda roar at them like that. EVER.
Prefect bathroom scene.... SO wrong! This movie is for children and you have Myrtle totally and blatantly coming on to Harry. :-s And the mermaid was awake, when she was asleep in the book, awake for Cedric though. Though I suppose that's kinda a minor nitpick.
Third Task was blah. I was like "Where are the Blast-Ended Skrewts? Where's the Sphinx? Why is this maze very una-maze-ing? (excuse the pun)" None of them were there. It was just like a normal maze for all intents and purposes. The only magical thing was it kinda closed up behind them a few times, and roots kinda grabbed all over Fleur and later Cedric. But for a "dangerous" task for wizards/witches it was way too tame. :\ And then Cedric and Harry were shovin at each other and shiz tryin to get to the cup. Nothin like that in the book. It was annoying, an important aspect of the book and they totally cut it down.
No argument between Dumbledore and Fudge about how Voldemort is back. :-s That kinda has a pretty big effect on the next book/movie. There's a rift there that people who didn't read the book won't know about. You need some of these things!!!
There were other things that bugged me, but nothing incredibly important. There were some nice additions in terms of scenes, like where they learn to dance and where they're in study hall (I'm guessing it's that anyway) and Snape keeps hitting them xD Though I wouldn't have been terribly upset if that had been cut and something from the book was in it's place. :-p
Feel like I ranted a lot. It was a good movie, really well made and many well done scenes, but it wasn't Harry Potter and the Goblet of Fire to me. It didn't stay true enough to the book in some places where it really should have.
End rant.